Mold for making commutators



Feb, M, H936.; ZOOSZ V. G. APPLE MOLD FOR MAKING COMMUTATORS OriginalFiled May 16, 1929 Patented Feb. 11, 1936 UNITED STATES PATENT OFFICEMOLD FOR MAKING COMMUTATORS Vincent G. Apple, deceased, late of Dayton,Ohio, by Herbert F. Apple, Edward M. Apple, and Gourley Darroch,executors, Dayton, Ohio 3 Claims.

This invention is a division of copending application Serial No.363,460, led May 16th, 1929, and relates to apparatus for makingcommutators of the class comprising a cylindrical row of spaced apartsegments of conductive material imbedded in a core of molded insulation.

The object of the invention is to provide a mold which will greatlyfacilitate the making of a commutator of this character.

rThis object is obtained in the structure hereinaiter described andillustrated in the accompanying drawing, wherein,

Fig. 1 shows a sheet metal blank such as may be used for makingcommutator segments.

Fig. 2 shows the blank Fig. 1 after it is bent to compose a segment.

Fig. 3 shows the body of the mold within which a cylindrical ro-Wvof thesegments are held while the core of insulation is molded within andbetween them.

Fig. 4 shows a set of the segments within the mold body as they appeartherein before the core of insulation is molded.

Fig. 5 is a vertical axial section through the complete mold having thecylindrical row of segments spaced and held therein and a quantity ofloose unmolded insulation sufficient for the core within the mold readyto be pressed within and between the segments.

Fig. 6 shows the mold Fig. 5 after it has been operated to force theinsulation core into permanent position.

Fig. 7 shows the completed commutator after it is removed from the mold.

Similar numerals refer to similar parts throughout the several views.

Referring now to the drawing, a segment blank I5 is cut from sheetmetal, preferably copper, one end I6 being tapered and having a hole I7therethrough while the other end is slitted on the lines I8 whereby itis divided into two outer parts I9 and a keystone shaped middle part 2|with a notch 22 at the extreme end.

To make a commutator segment 23 of the blank I5 it is bent as in Fig. 2where the body 24 of the blank, which is to form the brush track, iscurved to the radius of the commutator cylinder, the parts IB and I9 arebent downward and toward each other to form anchors which will beimbedded in the commutator core, and the keystone shaped part 2I is bentupwardly to form a riser for the segment, the notch 22 being providedfor making the winding connection.

Fig. 3 shows the body 26 of the mold 25 which is provided for locatingand holding the segments 23 in accurately spaced apart cylindricalformation while molding the core of insulation between them. In the topsurface of the body 26 are a series of keystone shaped pockets 2 withinwhich the risers 2I may be seated.. Pins 28 in the .base 29 of the moldare preferably provided to enter holes I'I in the lower -end of thesegments.

The pins 28 are Yprovided to keepthe lower ends of the segments frommoving toward 0r away from each other, but they are of advantage onlywhen the segments are relatively long and narrow, for in such a case the`holding of the segments at the one end by the riser may not effectivelyprevent the other end .from moving about. But where the segments arerelatively 15 short and wide the pins 28 A are preferably omitted, forin that case the segments may be held sufficiently by the `risersthemselves.l

A center plug 30 having a keyway 3l is concentrically supported in thebody 26 on the base 29 and is adapted to form the central axial openingthrough the commutator with an integral key of molded insulationextending inwardly from the wall of the opening.

Fig. 4 shows the same mold parts as are shown in Fig. 3 but with a setof segments 23 in place. The keystone shaped risers 2l of the segmentsare seated in the pockets 21 of the mold body, the pins 28 in the baseof the mold extending upwardly through the holes I'l of the segments. Itwill be seen that the segments 23, when placed in the mold parts asshown in Fig. 4, are securely held and accurately spaced apart so thatthe core of insulation may be molded within the cylindrical row and madeto extend between contiguous segments clear out to the outer diameter ofthe commutator.

With the segments 23 placed in the mold body 26 as shown in Fig. 4, astock ring 32 is securely fastened to the body 26 by the screws 33. Therisers 2l of the segments are fully as thick as the depth of the pockets27 whereby the stock ring when bolted in place securely clamps therisers and prevents even slight movement of the segments either axially,radially or circumferentially.

The mold and segments are now preferably brought to a relatively hightemperature and while they are so heated a charge 34 of unmoldedinsulation is placed into the stock ring 32. The plunger 35 is thenentered in the upper end of the stock ring 32 as shown in Fig. 5. Afterthe insulation 34 has absorbed sufficient heat from the mold to becomeplastic, the plunger 35 is pressed downward, forcing the insulationabout the plug 30 of the mold, and about the anchors I6 and I9 of thesegments, and into all the space between adjacent segments to the outerdiameter of the commutator. The insulating core is now hardened and thecommutator removed from the moldf A completed commutator is shown inFig. 7.

Conventional commutator molds usually comprise either no means at allfor spacing the commutator segments, in which case mica strips areassembled between the segments and a core molded within the assembly, orthe molds may have metal spacing strips extending radially inward fromthe inner wall of the mold, in which case the completed commutator hasair spaces only between the segments. A mold comprising means forholding a series of separate segments spaced apart and yet leave thespace between them vacant so that the insulation core may extend betweenthem is therefore broadly new, and with this view of the invention It isclaimed:

1. For making commutators from a series of separate segments each ofwhich has an outwardly turned riser at the one end and an inwardlyturned anchor at the other end, a mold comprising a hollow body in theform of a cup having a smooth interior equal to the diameter of thecommutator to be made, means on the upper edge of said cup for engagingsaid risers and means in the bottom of the cup for engaging saidanchors, both said engaging means holding said segments against radiallyinward movement in circumferentially spaced apart relation around theperiphery of the interior of the cup to compose of said segments ahollow cylinder having the spaces between adjacent segments entirelyvacant, and means to mold a single mass of insulation into the saidhollow cylinder and the said vacant spaces.

2. For making commutators from a series of separate segments each ofwhich has an outwardly turned riser at the one end and an inwardlyturned anchor at the other end, a mold comprising a hollow body in theform of a cup having a smooth interior of the diameter of the commutatorto be made, the upper edge of said cup having a series ofcircumferentially spaced apart pockets each adapted to contain andclosely iit one of said risers and the bottom of the cup having a seriesof circumierentialy spaced apart pins adapted to engage and hold thesaid anchors, said pockets and pins being so spaced as to hold thesegments against radially inward movement in circumferentially spacedapart relation around the periphery of the interior of the said cup tocompose of the segments a hollow cylinder having the spaces betweenadjacent segments entirely vacant, and means to mold a single mass ofinsulation into the said hollow cylinder and the said vacant spaces.

3. In a mold for making commutators from a series of individual segmentshaving risers, a

mold body having a cylindrical opening of the diameter of the commutatorand a series of circumferentially spaced pockets to receive said risersextending radially from said opening, a bottom member for closing thelower end of said tV opening, means on said bottom member for holdingthe ends of the segments against circumferential and radially inwardmovement, and means to mold a core of insulation between and within saidsegments.

HERBERT F. APPLE, EDWARD M. APPLE, GOURLEY DARROCH, Eecutors for VincentG. Apple, Deceased.

